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Solid‐state NMR characterization of motion in flexible polyurethane foams
Author(s) -
Moreland J. C.,
Wilkes G. L.,
Moreland C. G.,
Sankar S. S.,
Stejskal E. O.,
Turner R. B.
Publication year - 1994
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1994.070520901
Subject(s) - polyurethane , phase (matter) , materials science , mixing (physics) , lithium chloride , relaxation (psychology) , chloride , polymer , motion (physics) , molecule , solid state nuclear magnetic resonance , polymer chemistry , analytical chemistry (journal) , nuclear magnetic resonance , chemistry , composite material , physics , chromatography , organic chemistry , psychology , social psychology , quantum mechanics , metallurgy , classical mechanics
High‐resolution solid‐state 13 C‐NMR has been used to study the phase separation and molecular motion in two series of polyurethane foams. These two series differ by one possessing the additive of lithium chloride, LiCl. NMR relaxation times can map the motion throughout the polymer molecule and detect changes in that motion arising from either microseparation or phase mixing between the different segments. There are only slight changes in the soft segment T 1 p ( 13 C) values as well as an increase in the hard segment T 1 p ( 1 H) values with increase in the hard segment content for the foams studied. The T 1 p ( 1 H) and T 1 p ( 13 C) values do indicate that the phase separation of the hard and soft segments is similar for all foams. A decrease in the T 1 p ( 1 H) and T 1 p ( 13 C) values with increasing LiCl content indicates that the motion of the soft segments is restricted more by the hard segments. This is explained by more phase mixing in the foams containing the LiCl additive. © 1994 John Wiley & Sons, Inc.